3,7-dimethyloct-6-en-1-yn-3-ol

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Study period:

31/03/1992 - 08/09/1992

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Test was conducted similar to OECD Test Guideline No. 473, 1983, under GLP Standards and QA.

Cross-reference

Reason / purpose for cross-reference:

reference to same study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Report date:

1992

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)

Deviations:

no

Principles of method if other than guideline:

Not relevant

GLP compliance:

yes

Type of assay:

in vitro mammalian chromosome aberration test

Test material

Test material information

Constituent 1

Reference substance name:

3,7-dimethyloct-6-en-1-yn-3-ol

EC Number:

249-482-6

EC Name:

3,7-dimethyloct-6-en-1-yn-3-ol

Cas Number:

29171-20-8

Molecular formula:

C10H16O

IUPAC Name:

3,7-dimethyloct-6-en-1-yn-3-ol

Details on test material:

- Name of test material (as cited in study report): DL-Dehydrolinalool
- Physical state: liquid
- Storage condition of test material: room temperature

Method

Target gene:

Not relevant

Species / strain

Species / strain / cell type:

Chinese hamster Ovary (CHO)

Details on mammalian cell type (if applicable):

- Type and identity of media: CHO-K5 clone; Ham's F10 treatment medium
- Properly maintained: yes
- Periodically checked for Mycoplasma contamination: yes
- Periodically checked for karyotype stability: yes

Additional strain / cell type characteristics:

not applicable

Metabolic activation:

with and without

Metabolic activation system:

Phenobarbital-beta-naphthoflavone induced S-9 liver homogenate fraction from Füllinsdorf albino rats

Test concentrations with justification for top dose:

Without S9-mix (short time exposure):
3 h treatment time, 18 h recovery: 100, 200 and 300 ug/ml serum-free medium
3 h treatment time, 18 h recovery: 187 and 280 ug/ml culture medium
Without S9-mix (long time exposure term):
18 h treatment time: 93 and 187 ug/ml
20 h treatment time: 150 ug/ml
28 h treatment time: 94 and 188 ug/ml
30 h treatment time: 150 ug/ml
40 h treatment time: 150 ug/ml
With S9-mix: (short time exposure):
3 h treatment time, 18 h recovery: 100, 200 and 400 ug/ml serum-free medium
3 h treatment time, 18 h recovery: 187 and 374 ug/ml culture medium
Higher concentrations reduced the CFE by 50-95% (Without S9-Mix: 3h: 300 ug/ml; 18h: 187 ug/ml; 20h: 150 ug/ml; 28h: 188 ug/ml; With S9-Mix: 3h: 200, 400 ug/ml)

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: DMSO

Controls

Untreated negative controls:

yes

Remarks:

untreated

Negative solvent / vehicle controls:

yes

Remarks:

DMSO

True negative controls:

no

Positive controls:

yes

Positive control substance:

other: Bleomycin (direct-acting mutagen) and cyclophosphamide (promutagen)

Details on test system and experimental conditions:

METHOD OF APPLICATION: Incubation in medium (serum-free medium and culture medium)

DURATION
- Preincubation period: 1-2 days
Without S9-mix (short time exposure):
- Exposure duration: 3 hours treatment
- Expression time (cells in growth medium): 18 hours recovery
- Fixation time (start of exposure up to fixation or harvest of cells): 21 hours
Without S9-mix (long time exposure term):
- Exposure duration: 18, 20, 28, 30, and 40 hours treatment time
- Fixation time (start of exposure up to fixation or harvest of cells): 18, 20, 28, 30, and 40 hours
With S9-mix: (short time exposure):
- Exposure duration: 3 hours treatment time
- Expression time (cells in growth medium): 18 hours recovery
- Fixation time (start of exposure up to fixation or harvest of cells): 21 hours

SPINDLE INHIBITOR (cytogenetic assays): Colcemid, 0.2 µg/ml, last 2.5 hrs. of incubation

STAIN (for cytogenetic assays): Giemsa solution, approx. 9 min, 3 %

NUMBER OF REPLICATIONS:
Treatment groups: duplicate cultures
Negative controls: quadruplicate cultures
Positive controls: single cultures

NUMBER OF CELLS EVALUATED: 100 metaphase chromosome spreads per culture

DETERMINATION OF CYTOTOXICITY
- Method: Cells seeded in petri dishes were treated in parallel in order to determine the colony forming efficiency (CFE). Whenever possible the top
dose was chosen as the one which reduced the CFE by 50-75 %.

Evaluation criteria:

The test compound will considered to be clastogenic if statistically significant increases in the proportion of cells with structural chromosome
aberrations occur at one of its concentrations and if the incidence of aberrations at such data points exceeds the normal range. Numerical
chromosome changes are not reported.

Statistics:

The statistical evaluation of the data was performed by means of the "Fisher's Exact Test (Forbes, 1984: Microcomputer programs for mutation studies using the Fisher exact test or the binomial approximation. Mutat. Res.141, 205-210), two-tailed probability (Wyss, 1981: Exakter Test von F.A. Fischer DVA/TW 6.3.81). However the statistical analysis can only be a supportive criterium for the evaluation of the test data.

Results and discussion

Test results

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

positive

Remarks:

only in absence of the metabolizing system

Cytotoxicity / choice of top concentrations:

cytotoxicity

Remarks:

Dramatically reduced number of metaphases were observed

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

COMPARISON WITH HISTORICAL CONTROL DATA: The negative control values were within the generally accepted range.

Remarks on result:

other: strain/cell type: CHO cells

Remarks:

Migrated from field 'Test system'.

Any other information on results incl. tables

Dramatically reduced number of metaphases were observed at following concentrations:

3h -S9: > 374 ug/ml

3h +S9: >457/561 ug/ml

28h -S9: >280 ug/ml

18h -S9: >280 ug/ml

30h -S9: >200 ug/ml

40h -S9: >200 ug/ml

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative with metabolic activation
positive without metabolic activation at 150, 187, 188, 280 and 300 ug/ml

Under the experimental conditions described, DL-Dehydrolinalool induces genetic damage in cultured CHO cells at doses ranging from 150 to 300
ug/ml in absence of the S9 metabolic activation system. No clastogenic potential was noted in the presence of metabolic activation at concentrations up to 400 ug/ml which reduced the CFE by 80% (i.e. were cytotoxic).

Executive summary:

DL-Dehydrolinalool was assessed for its ability to induce chromosomal aberrations in cultured CHO cells in vitro.Without metabolic activation doses between 100 and 300 ug/ml were tested after short time exposure (3 hours) and between 93 and 188 ug/ml after long time treatment (18-40 hours). In presence of a metabolic activation mix prepared from the livers of phenobarbital-beta-naphthoflavone treated rats doses between 100 and 400 ug/ml were tested in two independent experiments.

The sensitivity of the test system and the activity of the metabolic activation were demonstrated by using the direct acting mutagen bleomycin and the promutagen cyclophosphamide as positive controls. Both substances increased significantly the rate of structural chromosome aberrations.

Exposure of the CHO cells to DL-Dehydrolinalool resulted in statistically significant increases of the rate of structural chromosome aberrations in absence of the metabolizing system only starting at 150 ug/ml. The presence of the S9 mix alleviated the genotoxic potential of the test compound.

It has however to be considered that DL-Dehydrolinaloot, is clastogenic under the described in vitro conditions.